Methods, apparatus and computer program products for associating local telephone numbers with emergency phone calls in a packet switched telephone system

ABSTRACT

A packet switched telephone system includes a packet switched routing apparatus. The packet switched routing apparatus selectively associates a local telephone number with a phone call based on a called telephone number, and routes the phone call based on the called telephone number. The local telephone number may be substituted for a calling telephone number when the called telephone number corresponds to a predefined number, such as an emergency number. When the called telephone number corresponds to an emergency number, the phone call may be routed with the substituted local telephone number to a Public Safety Access Point (PSAP) that services the local area of the subscriber.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/842,491, filed May 10, 2004, the disclosure of which is herebyincorporated herein by reference as if set forth in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to the field of switchedtelephony, and more particularly to apparatus, methods, and computerprogram products for providing voice communications over a packetswitched network, such as the Internet.

BACKGROUND OF THE INVENTION

The Internet has become a mainstream network for communicating not justdata, such as email and pictures, but also for providing real-timebi-directional voice communications. Voice-Over-Internet-Protocol (VoIP)is an industry standard that has evolved to enable users to place phonecalls through the Internet, instead of through the Public SwitchedTelephone Network (PSTN). A conventional phone may now be connected tothe Internet using an interface device that converts analog phonesignals to digital signals that can be communicated through theInternet. A phone call may thereby be communicated through the Internetto a VoIP provider, who converts the call back to an analog signal andplaces the call through a PSTN that is local to the called phone. A usercan thereby dial a telephone number in a conventional manner and havethe call routed through the Internet, instead of through a PSTN.

However, some telephone services may only be available to users who makecalls through a PSTN, and may not be available if the calls are insteadmade through the Internet. For example, when a user places a call to anemergency number, such as a “911” call, through a PSTN, the emergencycall is routed to a Public Safety Answering Point (PSAP). The locationof the caller and the phone number of the calling phone may beautomatically communicated to a PSAP operator, who can then route thecall to the proper emergency service provider.

Users who subscribe to VoIP services may elect to be assigned atelephone number that is not local to that user's local geographic ratecenter (i.e., a foreign telephone number). For example, a user whoresides in Atlanta, Ga., may elect to have a telephone number that islocal to Chicago, Ill. Accordingly, a VoIP telephone number may beforwarded to a PSAP that is not local to a caller, and/or it may notprovide useful information on the location of a caller.

SUMMARY OF THE INVENTION

Various embodiments of the present invention provide a packet switchedtelephone system that includes a packet switched routing apparatus thatis configured to selectively associate a local telephone number with aphone call based on a called telephone number, and is configured toroute the phone call based on the called telephone number. In somefurther embodiments of the present invention, the local telephone numberis substituted for a calling telephone number when the called telephonenumber corresponds to a predefined number, such as an emergency number.For example, when the called telephone number corresponds to anemergency number, the phone call may be routed with the substitutedlocal telephone number to a Public Safety Access Point (PSAP).

Accordingly, in some embodiments of the present invention, when a phonecall is made to an emergency telephone number, a local telephone numbermay be associated with the phone call as the calling telephone number.The phone call may then be routed based on the local telephone number toa portion of a public safety system that services the local area of asubscriber (i.e., a PSAP local to the subscriber). The location of thesubscriber may be automatically retrieved based on the local telephonenumber for use by emergency personnel. A subscriber may thereby call anemergency number from a non-local packet switched telephone number, buthave the emergency call routed to a local public safety system with thesubscriber's location information being retrieved in an automatedmanner.

In some other further embodiments of the present invention, the packetswitched routing apparatus includes a VoIP server that associates alocal telephone number and a packet switched telephone number with asubscriber. The VoIP server routes the phone call with the localtelephone number as the calling telephone number when the calledtelephone number corresponds to a predetermined number. The VoIP serverroutes the phone call with the packet switched telephone number as thecalling telephone number when the called telephone number does notcorrespond to the predetermined number.

In some other further embodiments of the present invention, the packetswitched routing apparatus includes a soft switch that associates alocal telephone number and a packet switched telephone number with asubscriber. The soft switch routes the phone call with the localtelephone number as the calling telephone number when the calledtelephone number corresponds to a predetermined number. The soft switchroutes the phone call with the packet switched telephone number as thecalling telephone number when the called telephone number does notcorrespond to the predetermined number.

Other systems, methods, and/or computer program products according toembodiments will be or become apparent to one with skill in the art uponreview of the following drawings and detailed description. It isintended that all such additional systems, methods, and/or computerprogram products be included within this description, be within thescope of the present invention, and be protected by the accompanyingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features of the present invention will be more readily understoodfrom the following detailed description of specific embodiments thereofwhen read in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of a packet switched telephone system thatroutes calls to a public safety system according to various embodimentsof the present invention;

FIG. 2 is a flow chart illustrating operations for routing phone callsin a packet switched telephone system according to various embodimentsof the present invention; and

FIG. 3 is another flow chart illustrating operations for routing phonecalls in a packet switched telephone system according to variousembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. However, this invention should not be construed aslimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the invention to those skilled in theart. Like numbers refer to like elements throughout.

It also will be understood that, as used herein, the term “comprising”or “comprises” is open-ended, and includes one or more stated elements,steps and/or functions without precluding one or more unstated elements,steps and/or functions. As used herein the term “and/or” includes anyand all combinations of one or more of the associated listed items.

The present invention may be embodied as systems, methods, and/orcomputer program products. Accordingly, the present invention may beembodied in hardware and/or in software (including firmware, residentsoftware, micro-code, etc.). Furthermore, the present invention may takethe form of a computer program product on a computer-usable orcomputer-readable storage medium having computer-usable orcomputer-readable program code embodied in the medium for use by or inconnection with an instruction execution system. In the context of thisdocument, a computer-usable or computer-readable medium may be anymedium that can contain or store the program for use by or in connectionwith the instruction execution system, apparatus, or device.

The computer-usable or computer-readable medium may be, for example butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus or device. More specificexamples (a nonexhaustive list) of the computer-readable medium wouldinclude the following: a portable computer diskette, a random accessmemory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), and a portable compact discread-only memory (CD-ROM). Note that the computer-usable orcomputer-readable medium could even be paper or another suitable mediumupon which the program is printed, as the program can be electronicallycaptured, via, for instance, optical scanning of the paper or othermedium, then compiled, interpreted, or otherwise processed in a suitablemanner, if necessary, and then stored in a computer memory.

The present invention is described below with reference to blockdiagrams and/or operational illustrations of methods, systems, andcomputer program products according to embodiments of the invention. Itis to be understood that the functions/acts noted in the blocks mayoccur out of the order noted in the operational illustrations. Forexample, two blocks shown in succession may in fact be executedsubstantially concurrently or the blocks may sometimes be executed inthe reverse order, depending upon the functionality/acts involved.

FIG. 1 is a block diagram of packet switched telephone system 100 thatroutes phone calls through a packet switched network to consumerpremises equipment (CPE) and to a public safety system 110 according tovarious embodiments of the present invention. The exemplary packetswitched telephone system 100 includes consumer premises equipment (CPE)120 and 160, a local access Internet provider 130, a packet switchedrouting apparatus 140, and trunk gateways 150 a-b.

The packet switched telephone system 100 allows phone calls to beinitiated and/or received via the CPE 120 through a packet switchednetwork, which for purposes of illustration only is referred to as theInternet, and such phone calls can be referred to as Voice Over InternetProtocol (VoIP) phone calls. The CPE 120 may be a computer with amicrophone, speaker, and software that is configured to convert voiceto/from a digital format that can be routed through the Internet.Alternatively, the CPE 120 may be a conventional phone that is connectedthrough a Voice Over Internet Protocol (VoIP) access device to theInternet.

The local access Internet provider 130 provides a local interfacebetween the CPE 120 and the packet switched routing apparatus 140. Thelocal access Internet provider 130 may be, for example, a localtelephone company that provides access to the Internet through a dial-upconnection and/or through a digital subscriber line (DSL), a cableTV/communications company that provides a cable modem connection to theInternet, and/or a wireless operator that provides cellular datacommunications to the Internet over a wireless interface.

To setup VoIP services, a subscriber registers with a VoIP serviceprovider and is assigned one or more packet switched telephone numbers.A subscriber can request packet switched telephone numbers that arelocal to the subscriber (e.g., the number is local to the subscriber'slocal geographic rate center) and/or that are not local to thesubscriber. For example, a subscriber may reside in Atlanta, Ga., andmay request packet switched telephone numbers that are local to New YorkCity, N.Y. and to San Diego, Calif., both of which are not local to thesubscriber's Atlanta Ga. location.

When a subscriber requests only non-local telephone numbers, thesubscriber is also assigned a local telephone number that is associatedwith the location of the subscriber (e.g., a telephone number having anarea code and/or other prefix that is associated with the subscriber'slocal geographic rate center, such as Atlanta, Ga.). For example, when asubscriber does not request a local packet switched telephone number, aVoIP service provider may look-up an available local telephone numberand assign it to the subscriber. The VoIP service provider may not makethe subscriber aware of the assigned local telephone number and/or itmay take steps to prevent it from being used by a subscriber to initiatephone calls.

The assigned local telephone number does not need to be a callabletelephone number, for example it may be a telephone number that isreserved or otherwise not usable for placing a call from thesubscriber's location. Moreover, the assigned local telephone number maynot be unique to a particular subscriber, and may instead be associatedwith a geographic area, such as a building or city block. Assigninglocal telephone numbers that are not necessarily unique to a subscribermay conserve the number of assigned telephone numbers, but may result ina corresponding decrease in the accuracy with which the assignedtelephone number can be used to determine the location of a subscriber.

The location of the subscriber (e.g., street address and/or GPScoordinates) and the local telephone number, which may be a local packetswitched telephone number requested by a subscriber or local telephonenumber assigned by the VoIP service provider, are provided to the publicsafety system 110. The public safety system 110 may store the localtelephone number and location in an automatic location information (ALI)database 112. The ALI database 112 may be, for example, a database thatis presently available from Intrado Inc.

The packet switched routing apparatus 140 routes phone calls based onthe called telephone number (i.e., the telephone number to which thecall is directed). For example, it may route a phone call from the CPE120 through the trunk gateway 150 a and a PSTN 152, which includes atermination line for the called telephone number, to the CPE 160. TheCPE 160 may be a conventional plain old telephone system (POTS)telephone.

When the called telephone number is a predetermined number, such as“911” or another emergency number, the packet switched routing apparatus140 determines whether the calling telephone number (i.e., the telephonenumber from which the call originated) is local to the subscriber and,if it is local, it routes the phone call with the calling telephonenumber. When the calling telephone number is not local to thesubscriber, the packet switched routing apparatus 140 associates a localtelephone number for the subscriber with the phone call and routes thephone call. The local telephone number may be substituted for, and usedas, the calling telephone number associated with the phone call. Thelocal telephone number may be a local packet switched telephone numberthat was requested by a subscriber or it may be a local telephone numberassigned by the VoIP service provider when the subscriber did notrequest a local packet switched telephone number.

When the called telephone number is an emergency number, the packetswitched routing apparatus 140 routes the phone call based on the calledtelephone number and the calling telephone number through the trunkgateway 150 b to a portion of the public safety system 110 that servicesthe local area of the subscriber. The phone call can be routed in thepublic safety system 110 through a public safety access point (PSAP)tandem switch 114, which obtains routing information from the ALIdatabase 112 and routes the phone call to a PSAP 116 that services thelocal area of the subscriber. The PSAP 116 obtains the subscriber'slocation information from the ALI database 112 based on the callingtelephone number, which may allow emergency personnel to determine thelocation of a caller.

The packet switched routing apparatus 140 can include a VoIP server 142and a soft switch 144. The VoIP server 142 may be, for example, aBroadWorks platform by BroadSoft, and can include subscriber informationused for routing calls to/from subscribers. The soft switch 144 may be,for example, a Siemens hiQ 8000 Softswitch, and can provide a bridgebetween the Internet and the trunk gateways 150 a-b and/or otherequipment in a public switched telephone network. The VoIP server 142and/or the soft switch 144 may perform one or more of the operations forchecking whether a called telephone number corresponds to apredetermined number, determining whether the calling telephone numberis local to a subscriber, and/or associating a local telephone numberwith a phone call. For example, the VoIP server 142 and/or the softswitch 144 may associate a local telephone number and a packet switchedtelephone number with a subscriber, and route a phone call with thelocal telephone number or with the packet switched telephone number as acalling telephone number based on whether the called telephone numbercorresponds to a predetermined number. The local telephone numbers and apacket switched telephone numbers associated with subscribers may beretained in a subscriber telephone number database 146 that can bequeried, or otherwise accessed, by the VoIP server 142 and/or the softswitch 144.

Accordingly, in some embodiments of the present invention, when a phonecall is made to an emergency telephone number, a local telephone numberis associated with the phone call as the calling telephone number. Thephone call may then be routed based on the local telephone number to aportion of a public safety system that services the local area of thesubscriber, and the location of the subscriber may be automaticallyretrieved and used by emergency personnel. A VoIP subscriber may therebycall an emergency number from a non-local packet switched telephonenumber, but have the emergency call routed to a local public safetysystem with the subscriber's location information being retrieved in anautomated manner.

Although FIG. 1 illustrates an exemplary packet switched telephonesystem 100, it will be understood that the present invention is notlimited to such a configuration, but is intended instead to encompassany configuration capable of carrying out the operations describedherein. For example, although only two CPEs 120 and 160 and two trunkgateways 150 a-b have been shown for illustration purposes, it will beunderstood that the packet switching routing apparatus 140 wouldgenerally route phone calls to/from thousands of VoIP subscribersthrough numerous trunk gateways. Moreover, it is to be understood thatalthough the packet switched telephone system 100 has been described inthe context of the Internet, it may be used to route phone calls throughany packet switched network. Moreover, CPEs may communicate with a localaccess Internet provider and/or a packet switched routing apparatusacross a wireless interface such as, for example, a cellular interface(e.g., General Packet Radio System (GPRS), Enhanced Data Rates forGlobal Evolution (EDGE), Global System for Mobile Communications (GSM)),a wireless local area network interface (e.g., WLAN, IEEE 802.11), aBluetooth interface, another RF communication interface, and/or anoptical interface.

FIG. 2 is flow chart of operations for routing phone calls in a packetswitched telephone system according to various embodiments of thepresent invention. At Block 200, a phone call is received. At Block 210,a local telephone number is associated with a phone call based on thecalled telephone number, and the phone call is routed based on thecalled telephone number. Further embodiments of these operations aredescribed now with reference to FIG. 3.

At Block 300, a phone call is received at, for example, the packetswitched routing apparatus 140 shown in FIG. 1. At Block 310, a decisionis made as to whether the called telephone number corresponds to anemergency number (e.g., “911”). When the called telephone number doesnot correspond to an emergency number, the phone call is routed at Block320 based on the called telephone number. When the called telephonenumber corresponds to an emergency number, a further determination ismade at Block 330 as to whether the calling telephone number is local tothe subscriber who is associated with the phone call. When the callingtelephone number is determined to be local (at Block 330), then at Block350 the phone call is routed based on the calling telephone number andthe called telephone number to a public safety system that services thegeographic area of the subscriber.

When the calling telephone number is determined to be non-local (atBlock 330), then at Block 340 a local telephone number is substitutedfor the calling telephone number. The local telephone number may beanother telephone number that was requested by the subscriber, such aswhen a VoIP subscriber requests a local packet switched telephone numberand one or more non-local packet switched telephone numbers, or it maybe a local telephone number that is assigned to the subscriber by, forexample, a VoIP service provider. At Block 340, the local telephonenumber is substituted for the calling telephone number. The phone callis then routed at Block 350 with the substituted local telephone numberto the public safety system that services the geographic area of thesubscriber, which is determined based on the substituted callingtelephone number.

In the drawings and specification, there have been disclosed typicalpreferred embodiments of the invention and, although specific terms areemployed, they are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being set forthin the following claims.

1. A packet switched telephone system, comprising: a Voice Over InternetProtocol (VoIP) server that is configured to route a phone call that isdirected to a Public Safety Access Point (PSAP) by substituting a localtelephone number for a calling telephone number from which the phonecall originated, and to route the phone call with the substituted localtelephone number to the PSAP, wherein the calling telephone number isdifferent than the local telephone number, and the substituted localtelephone number can be called by an operator at the PSAP to return thephone call to the subscriber through a Public Switched Telephone Network(PSTN).
 2. The packet switched telephone system of claim 1, wherein: theVoIP server is further configured to substitute the local telephonenumber for the calling telephone number only when a called telephonenumber for the phone call corresponds to an emergency number for thePSAP.
 3. The packet switched telephone system of claim 1, wherein: theVoIP server is further configured to route the phone call with thesubstituted local telephone number to the PSAP in response to the calledtelephone number corresponding to an emergency number for the PSAP, andto route the phone call with the calling telephone number and withoutsubstitution of the local telephone number in response to the calledtelephone number not corresponding to the emergency number.
 4. Thepacket switched telephone system of claim 1, wherein: the VoIP server isfurther configured to associate the local telephone number and a packetswitched telephone number with the subscriber, to route the phone callwith the substituted local telephone number as the calling telephonenumber in response to a called telephone number for the phone callcorresponding to an emergency number for the PSAP, and to route thephone call with the packet switched telephone number as the callingtelephone number and without substitution of the local telephone numberin response to the called telephone number not corresponding to theemergency number.
 5. The packet switched telephone system of claim 1,further comprising: an Automatic Location Information (ALI) databasethat is configured to associate subscriber location information withsubscriber local telephone numbers; and the PSAP is configured to usethe substituted local telephone number from the received phone call tolook-up in the ALI database the corresponding subscriber locationinformation.
 6. The packet switched telephone system of claim 1, furthercomprising: a local telephone number database that associates localtelephone number with packet switched telephone number for subscribers,wherein the VoIP server is further configured to respond to the calledtelephone number corresponding to an emergency number for the PSAP byquerying the local telephone number database using the packet switchedtelephone number received as the calling telephone number for the phonecall to retrieve the corresponding local telephone number, and bysubstituting the local telephone number for the packet switchedtelephone number as the calling telephone number for the phone call. 7.A method of routing phone calls in a packet switched telephone system,the method comprising: in response to receiving a phone call at a VoiceOver Internet Protocol (VoIP) server, substituting a local telephonenumber for a calling telephone number from which the phone calloriginated in response to the phone call being directed to a PublicSafety Access Point (PSAP); and routing the phone call with thesubstituted local telephone number to the PSAP, wherein the callingtelephone number is different than the local telephone number, and thesubstituted local telephone number can be called by an operator at thePSAP to return the phone call to the subscriber through a PublicSwitched Telephone Network (PSTN).
 8. The method of claim 7, wherein:the local telephone number is substituted for the calling telephonenumber only when a called telephone number for the phone callcorresponds to an emergency number for the PSAP.
 9. The method of claim7, wherein: the phone call is routed to the PSAP with the substitutedlocal telephone number to the PSAP in response to the called telephonenumber corresponding to an emergency number for the PSAP; and the phonecall is routed through the packet switched telephone system with thecalling telephone number and without substitution of the local telephonenumber in response to the called telephone number not corresponding tothe emergency number.
 10. The method of claim 7, further comprising:associating the local telephone number and a packet switched telephonenumber with the subscriber at the VoIP server; routing the phone callwith the substituted local telephone number as the calling telephonenumber to the PSAP in response to a called telephone number for thephone call corresponding to an emergency number for the PSAP; androuting the phone call through the packet switched telephone system withthe packet switched telephone number as the calling telephone number andwithout substitution of the local telephone number in response to thecalled telephone number not corresponding to the emergency number. 11.The method of claim 7, further comprising: associating subscriberlocation information with subscriber local telephone numbers within anAutomatic Location Information (ALI) database; and accessing the ALIdatabase from the PSAP using the substituted local telephone number fromthe received phone call to look-up the corresponding subscriber locationinformation.
 12. The method of claim 7, further comprising: associatinglocal telephone number with packet switched telephone number forsubscribers within a local telephone number database; responding to thecalled telephone number corresponding to an emergency number for thePSAP by querying the local telephone number database using the packetswitched telephone number received as the calling telephone number forthe phone call to retrieve the corresponding local telephone number formthe local telephone number database; and substituting the localtelephone number for the packet switched telephone number as the callingtelephone number for the phone call.
 13. A computer program product forrouting calls in a packet switched telephone system, the computerprogram product comprising: a computer readable storage medium havingcomputer readable program code embodied therein that comprises: computerreadable program code that is configured to be executed by a Voice OverInternet Protocol (VoIP) server to route a phone call that is directedto a Public Safety Access Point (PSAP) by substituting a local telephonenumber for a calling telephone number from which the phone calloriginated, and to route the phone call with the substituted localtelephone number to the PSAP, wherein the calling telephone number isdifferent than the local telephone number, and the substituted localtelephone number can be called by an operator at the PSAP to return thephone call to the subscriber through a Public Switched Telephone Network(PSTN).
 14. The computer program product of claim 13, furthercomprising: computer readable program code that is configured to beexecuted by the VoIP server to substitute the local telephone number forthe calling telephone number only when a called telephone number for thephone call corresponds to an emergency number for the PSAP.
 15. Thecomputer program product of claim 13, further comprising: computerreadable program code that is configured to be executed by the VoIPserver to route the phone call with the substituted local telephonenumber to the PSAP in response to the called telephone numbercorresponding to an emergency number for the PSAP, and to route thephone call with the calling telephone number and without substitution ofthe local telephone number in response to the called telephone numbernot corresponding to the emergency number.
 16. The computer programproduct of claim 13, further comprising: computer readable program codethat is configured to be executed by the VoIP server to associate thelocal telephone number and a packet switched telephone number with thesubscriber, to route the phone call with the substituted local telephonenumber as the calling telephone number in response to a called telephonenumber for the phone call corresponding to an emergency number for thePSAP, and to route the phone call with the packet switched telephonenumber as the calling telephone number and without substitution of thelocal telephone number in response to the called telephone number notcorresponding to the emergency number.
 17. The computer program productof claim 13, further comprising: computer readable program code that isconfigured to be executed by an Automatic Location Information (ALI)database to associate subscriber location information with subscriberlocal telephone numbers; and computer readable program code that isconfigured to be executed by the PSAP to use the substituted localtelephone number from the received phone call to look-up in the ALIdatabase the corresponding subscriber location information.
 18. Thecomputer program product of claim 13, further comprising: computerreadable program code that is configured to be executed by a localtelephone number database to associate local telephone number withpacket switched telephone number for subscribers; and computer readableprogram code that is configured to be executed by the VoIP server torespond to the called telephone number corresponding to an emergencynumber for the PSAP by querying the local telephone number databaseusing the packet switched telephone number received as the callingtelephone number for the phone call to retrieve the corresponding localtelephone number, and by substituting the local telephone number for thepacket switched telephone number as the calling telephone number for thephone call.